1. Field of the Invention
The present invention relates generally to fluid dispensing devices. More particularly, the invention concerns a novel medicament dispenser for dispensing medicinal fluids, such as plasma expanders of the character used to replace traditional blood based products, to ambulatory patients that uniquely comprise a fluid warming or cooling component that selectively either heats or cools the fluid being dispensed by non-electric means.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
Many people die annually from hemorrhages. Treatment for severe hemorrhage usually requires the immediate and rapid infusion of critical fluids to prevent shock by replacing lost blood volume. To conduct this fluid resuscitation efficaciously in an austere environment, the medical professional must be able to easily transport the delivery system and fluid, and then initiate its use under significant logistical constraints. Furthermore, multi-step and time consuming methods for beginning fluid resuscitation can reduce a medical professional's ability to save lives in triage situations where a large number of patients are injured and in need of immediate medical attention.
In order to maximize the chance of survival, fluid resuscitation is often necessary where the casualty must replace the blood volume lost from the wound. Similarly, the use of IV fluids to restore intravascular volume is considered the best way to manage a severe burn casualty and replenish fluids lost in the first 24 hours. Furthermore, fluid warming is often needed to prevent the onset of hypothermia in trauma patients suffering from catastrophic hemorrhage, where military studies suggest the practice of warming IV fluids prior to administration has significantly decreased the rate of preventable deaths. Accidental or uncontrolled hypothermia is also a well-recognized problem among trauma patients, requiring immediate clinical intervention. Moreover, up to 60% of patients admitted to regional trauma centers can be hypothermic.
Although electronic portable fluid warming devices are currently available, they are not optimal for austere environments where weight and cube are of great concern. Current technologies typically rely on extremely heavy and bulky proprietary batteries, or electricity, that the medical professional must carry in addition to IV fluid bags, thereby eliminating space for other necessary medical supplies. Additionally, current technologies are not designed for direct integration to the IV fluid solution or delivery system modality. In other words, in addition to carrying the IV fluid bags, the medic must carry a separate fluid warming device and a separate battery; altogether which occupy more space and weight than the medic can afford. The invention described herein is a chemically driven fluid warming component/apparatus which would integrate in the dispenser or downstream of the dispenser on the administration line, without adding substantial weight or cube to the overall system. Because the technology relies on chemically generated heat, the need for electricity or proprietary batteries is eliminated, making it possible to heat fluids in austere environments where, previously, warming IV fluids was very cumbersome.
Separate to electronic fluid warmers, other fluid warming “sleeves” or “hot packs” exist that can generate enough heat for an IV bag. Contrary to the fluid warming apparatus described herein, however, the sleeves and heat packs require several minutes to an hour to generate enough heat to warm the fluids to the necessary temperature. The length of time it takes to heat fluids with these warmers is insufficient in environments where the rapid delivery of fluids is required to prevent the casualty from hemorrhaging. Therefore, warming sleeves and hot packs also do not serve as ideal solutions in a trauma environment.
By way of additional background, administering intravenous fluids is a complex task that is even more difficult when intravenous volume IV replacement must be accomplished in the field. Very specific guidelines exist regarding appropriate physiological parameters that caregivers should use to identify which casualties actually require intravenous volume IV replacement in the field. Once intravenous or intra-osseous access is obtained and secured, current technology requires the caregiver to assemble the components of the IV solution prior to administration. A drip chamber must be connected to the fluid bag, the connecting line must be flushed, and then the line must be connected to the infusion site. When utilizing an intra-osseous site, the fluid bag then must be used in conjunction with a pressure infusing device to ensure appropriate flow rates. The complex logistical requirements for ordering, obtaining and storing appropriate medical supplies make the current technology most difficult. Further, the complexity of the process significantly jeopardizes safe and effective patient care within this environment.
As previously mentioned, in order to maximize the chance of survival, fluid resuscitation is often necessary where the casualty must replace the blood volume lost from the wound. Similarly, the use of IV fluids to restore intravascular volume is considered the best way to replenish fluids lost in the first 24 hours. In certain instances, fluid cooling, rather than fluid heating is needed to prevent IV fluids from reaching dangerously hot temperatures. Extremely hot IV fluids can cause tissue damage and hemolysis, a condition that is characterized by the breakdown of the red blood cell's membrane. Hot fluids can also be a disadvantage in treating heat-stroke casualties in the desert, or other high temperature environments. For example, the average daily temperatures in Iraq and Afghanistan, for example, can be in excess of 54° C. (130° F.) and temperatures exceeding 52.2° C. (126° F.) have been shown to damage tissue and blood cells. Although fluids can be stored at safe temperatures at higher level echelons of care, the medic in the austere environment (echelon 1) is at the mercy of the ambient temperature of the environment.
Although portable fluid cooling systems are currently available, they are not optimal for austere environments where weight, cube, and time required to cool are of great concern. Current electronic technologies are bulky, complex, and not suitable for austere environments due to weight and cube concerns. Alternatively, non-electric cooling pouches require the time consuming step of placing the IV fluid bag in the cooler and waiting 15 or more minutes; a step that is both time consuming and logistically complex as it requires the medic to carry both the IV fluid bag and the cooling pouch. The length of time it takes to cool fluids with these cooling systems is insufficient in environments where the rapid delivery of fluids is required to prevent the casualty from hemorrhaging.
The invention described herein is a chemically driven fluid cooling component/apparatus which would integrate in the dispenser or downstream of the dispenser on the administration line, without adding substantial weight or cube to the overall system. Because the technology relies on chemically generated cooling, the need for electricity or proprietary batteries is eliminated, making it possible to cool fluids in austere environments, where previously cooling IV fluids was very cumbersome. This invention with IV fluid dispenser and the integrated fluid cooling component as a self-contained unit would have significant logistical benefits over the currently used and disparate flexible solution bag, fluid coolers, and heavy batteries.
In an effort to overcome the drawbacks discussed in the preceding paragraphs, a number of different types of medicament dispensers for dispensing medicaments to ambulatory patients have been suggested. In this regard, one of the most versatile and unique fluid delivery apparatus developed in recent years is that developed by one of the present inventors and described in U.S. Pat. No. 7,220,245. This apparatus comprises a compact fluid dispenser for use in controllably dispensing fluid medicaments, such as antibiotics, oncolylotics, hormones, steroids, blood clotting agents, analgesics, and like medicinal agents from prefilled containers at a uniform rate. The dispenser uniquely includes a stored energy source that is provided in the form of a substantially constant-force, compressible-expandable wave spring that provides the force necessary to continuously and uniformly expel fluid from the device reservoir. The device further includes a fluid flow control assembly that precisely controls the flow of medicament solution to the patient.
The unique apparatus of the present invention for dispensing medicaments to a patient comprises an improvement of the apparatus described in U.S. Pat. No. 7,220,245 in that, among other things, the apparatus includes a novel non-electric means for controllably heating, or alternatively cooling the medicaments to be delivered to the patient. More particularly, the present invention uniquely provides an IV fluid dispenser and an integrated fluid warming, or cooling component as a self-contained unit that has significant logistical benefits over the currently used and disparate flexible solution bag, electronic fluid warmer and heavy batteries.